We hypothesize that the decidual choriogonadotrophin-inhibitory protein (DCIP), described by our in vitro studies may be an inhibitory regulator for choriogonadotropin production during pregnancy. Thus, DCIP may have roles in the diagnosis of early pregnancy disorders, treatment of gestational and nongestational trophoblastic disease, and in birth control. A pilot study will determine the quantity of DCIP in serum at different stages of gestation once an RIA for measuring DCIP has been developed. Preliminary studies have been performed on 6 serum samples; approximately 200 individuals (nonpregnant controls and male controls, along with women at varying stages in pregnancy) will be studied in the coming year.